New Homelabber, new R720. Seeking help.

Hey guys! Long time listener, first time caller. Couple questions, but first a little background.

I have a 24TB bare metal FreeNAS box that’s been humming along for a couple years and I recently decided to get into homelabbing. I'm handling a lot more IT functions at my current job and I think I'm going to be offered a new job as Technical Support Specialist for a school district and it would be helpful to gain some more knowledge about server computing and enterprise systems. Anyway, my current employer gifted me an R210ii they weren’t using, so I set up Server 2016 and some VM’s (PfSense, Ubuntu, Windows 10, Server 2016 for AD, DHCP, DNS).

I just bought a Dell R720 with a 3.5” chassis and have 2x 1TB SATA SSD’s coming. I plan on filling the rest of the drive trays with large capacity SAS or SATA drives. The idea is that I’ll run PfSense, PiHole and OpenVPN on the R210II and then use the R720 for everything else, including another fileserver. From some of the reading I’ve done about RAID controllers and FreeNAS (and since I’m trying to expand my IT knowledge), I was thinking I’d just run the fileserver in Windows this time around.

Now for the questions, since I’m pretty new to all of this:

• What brand/model of large capacity drives would you guys recommend? I was looking at the 4-6TB WD Golds, but really have no idea. I also have a single 8TB WD Red that’s just sitting around, so maybe I just get 5 more of those.

• What RAID setup would you guys recommend? I was thinking 2x SSD’s in RAID1 for OS’s, 6x SAS or SATA in RAID 6 for storage.

• Any good tutorials or resources for the setup of the drives? I’ll be running Windows Server 2016 and using a H710p controller.

• What am I not asking that I should be asking?